package ctgu.java;

public class TwoIntegers {

	  public int sum(int n, int m) {
	    // 前置断言
		int sum = n +m;
	    assert n >= 1 && n <= 99;
	    assert m >= 1 && m <= 99;
	    assert sum<100;
	    return sum;
	  }
	  
	  public int sub(int n, int m) {
		    // 前置断言
			int sub = n -m;
		    assert n >= 1 && n <= 99;
		    assert m >= 1 && m <= 99;
		    assert sub>=0;
		    assert sub<100;
		    return sub;
		  }
	}